WIND 7. Blade Element Analysis

How many elements is a blade broken into for analysis?

• 5

• 10

• 15

• 20

What is the purpose of slicing the blade in the analysis?

• To see the color

• To measure the length

• To view an airfoil

• To weigh the blade.

What is a resultant velocity?

• A scalar quantity with only magnitude

• A vector with direction and magnitude

• A measure of temperature

• A type of energy

Which of the following is true about the resultant velocity in the context of airfoils?

• It is irrelevant to lift and drag

• It is a wind speed in meters per second

• It has no direction

• It is a constant value

Tags

NGSS.HS-PS2-1

What is the direction of the lift force in relation to the resultant velocity?

• Parallel

• Perpendicular

• Opposite

• Same direction

Which of the following factors does the lift depend on?

• Density of air

• Resultant velocity

• Area of the blade element

• All of the above

What is the equation for drag?

What is the effect of the axial force on wind turbine blades?

• It causes the blades to rotate.

• It pushes the blades back toward the tower.

• It has no effect on the blades.

• It increases the lift force.

What is the tangential force in the context of wind turbines?

• The force that causes the blade to rotate.

• The force that pushes the blade back toward the tower.

• The force that aligns with the x-axis.

• The force that increases the lift.

What is the formula for torque in a rotor blade system?

• Torque (Nm) = Axial Force (N) × Radius of blade element (m)

• Torque (Nm) = Resultant Force (N) × Radius of blade element (m)

• Torque (Nm) = Tangential Force (N) × Radius of blade element (m)

• Torque (Nm) = Wind Force (N) × Radius of blade element (m)